Boxed in

Since writing a column about the dilemma of many moderate Republicans in this presidential race, I have heard from and talked with a number of people whose point of view is well expressed in a letter from a woman from Connecticut.

''In a recent column (you) listed the many things that 'moderate' Republicans did not like about what the President had done and is doing, and plans to do, yet you report that they are still going to vote for him because they like the man. Talk about a 'cult of personality'!''

She continues:

''I for one, have no intention of doing so, and this does not mean that I will 'bolt the party.' I have watched this party move further to the right over the past 20 years, up to its present despicable platform. In each election I have tried to cast my vote to the best of my conscience, hoping to see this party move itself into the present mainstream, or more to the center of the nation's thinking. It has not been easy. To be honest, I have not cast a vote in good conscience since Dwight Eisenhower.''

How would she vote, then? Would she cross over and vote for Walter Mondale? This didn't seem to be her intention. Might she end up by not voting at all for president? That seemed a possibility.

But I've come to believe that this woman is speaking for a lot of Republicans who feel their party credentials are as good as anyone else's and who are not at all sure whether they will vote for the President.

They say they are boxed in. They don't know where to go. Mr. Mondale is too liberal for their taste. Further, they don't like to vote Democratic.

But they are not caught up in Mr. Reagan the man and his personality. They believe he is wrong on several church-state positions. They don't find him sensitive to the need to work out an end to the arms race (despite his meeting with Andrei Gromyko). And they don't think he is as concerned as he should be about the plight of the disadvantaged, particularly the blacks.

Most of those I'm hearing from are women. Some fault the President for not backing the Equal Rights Amendment. But some say they would just like to see more evidence, beyond some appointments, of presidential concern for equality for women, particularly in the field of job opportunity and pay.

Most of these GOP moderates say they were learning to live with Reagan, although uncomfortably, until he allowed the right wing to dictate the party platform. It was then that their resistance to Reagan began to harden and doubts about how they could vote began to take shape.

Do these less-than-satisfied Republicans make up a ''secret vulnerability'' for Mr. Reagan, one that is not showing up in the polls but that could make itself felt at the election? This has to remain what political writers call an ''imponderable.''

It is arguable that the Republican moderate element in the party is still alive, well, and potent and big enough to be a force in moving an election one way or another.

If there are millions of Republicans who have become disenchanted with Reagan , it is possible that their nonvotes or grudging votes for Mondale, might become decisive. But such a scenario doesn't seem likely unless the race becomes, as they say, a horse race.

More than anything else, it seems, this rising voice of dissent over Reagan and his policies from people in good standing within the Republican Party is a reminder that the GOP, split for years and years, has not become monolithic and right wing in coloration.

The old Rockefeller wing of the party still exists, particularly in the Northeast. For most Republican moderates, Ronald Reagan was an unknown in 1980. They accepted him when they could not nominate George Bush. And they enjoyed the idea of having a Republican once again in the White House.

For many, however, Reagan isn't measuring up. Some are going to vote for him, but with less than enthusiasm. Others, like the woman from Connecticut, probably won't. And there are clearly a lot of others, at this point, who don't know how they are going to vote.

These moderate Republicans are finding this election extremely frustrating.